Three people assaulted a security guard at a Brackley supermarket this morning.
Northamptonshire Police said the attack happened during a delivery to Tesco in Oxford Road, Brackley at around 6.45am today (Tuesday).
The gang made off with a cash box before getting into a vehicle and driving off.
A police spokeswoman said the victim was taken to hospital but is not believed to have sustained serious injuries.
Officers investigating the incident would like to speak to anyone who may have any information about what happened this morning or who may have seen anyone or a silver VW Golf acting suspiciously in the area.
Witnesses or anyone with information about this incident can call police on 101 or Crimestoppers anonymously on 0800 555 111.